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Related papers: Fermi Velocity Modulation in Graphene by Strain En…

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In this work we investigate the effects of a Fermi velocity modulation in a valley filter in graphene created by a combination of a magnetic and electric barrier. With the effective Dirac equation of the system, we use the transfer matrix…

Mesoscale and Nanoscale Physics · Physics 2020-01-22 A. R. S. Lins , Jonas R. F. Lima

Currently there is a lively discussion concerning Fermi velocity renormalization in twisted bilayers and several contradicted experimental results are reported. Here we study electronic structures of the twisted bilayers by scanning…

Materials Science · Physics 2015-11-18 Long-Jing Yin , Jia-Bin Qiao , Wei-Jie Zuo , Wei Yan , Rui Xu , Rui-Fen Dou , Jia-Cai Nie , Lin He

We study the renormalization of the Fermi velocity by the long-range Coulomb interactions between the charge carriers in the Dirac-cone approximation for the effective low-energy description of the electronic excitations in graphene at half…

High Energy Physics - Phenomenology · Physics 2015-01-13 C. Popovici , C. S. Fischer , L. von Smekal

The aim of this work is to study the electron transport in graphene with impurities by introducing a generalization of linear response theory for linear dispersion relations and spinor wave functions. Current response and density response…

Mesoscale and Nanoscale Physics · Physics 2014-07-28 Juan Sebastian Ardenghi , Pablo Bechthold , Paula Jasen , Estela Gonzalez , Alfredo Juan

Using first-principles techniques, we calculate the renormalization of the electron Fermi velocity and the vibrational lifetimes arising from electron-phonon interactions in doped bilayer graphene and in graphite and compare the results…

Materials Science · Physics 2008-12-23 Cheol-Hwan Park , Feliciano Giustino , Marvin L. Cohen , Steven G. Louie

We resolve some apparent discrepancies between two different models for curved graphene: the one based on tight binding and elasticity theory, and the covariant approach based on quantum field theory in curved space. We demonstrate that…

Mesoscale and Nanoscale Physics · Physics 2012-06-05 Fernando de Juan , Mauricio Sturla , Maria A. H. Vozmediano

In this work we investigate the influence of a Fermi velocity modulation on the Fano factor of periodic and quasi-periodic graphene superlattices. We consider the continuum model and use the transfer matrix method to solve the Dirac-like…

Mesoscale and Nanoscale Physics · Physics 2017-11-22 Jonas R. F. Lima , Anderson L. R. Barbosa , C. G. Bezerra , Luiz Felipe C. Pereira

We demonstrate terahertz time-domain spectroscopy (THz-TDS) to be an accurate, rapid and scalable method to probe the interaction-induced Fermi velocity renormalization {\nu}F^* of charge carriers in graphene. This allows the quantitative…

We study uniaxially strained graphene under the influence of non-uniform magnetic fields perpendicular to the material sample with a coordinate independent strain tensor. For that purpose, we solve the Dirac equation with anisotropic Fermi…

Strongly Correlated Electrons · Physics 2018-06-12 Yajaira Concha Sanchez , Adolfo Huet , Alfredo Raya , David Valenzuela

Within the tight binding approximation, we study the dependence of the electronic band structure and of the optical conductivity of a graphene single layer on the modulus and direction of applied uniaxial strain. While the Dirac cone…

Mesoscale and Nanoscale Physics · Physics 2010-01-15 F. M. D. Pellegrino , G. G. N. Angilella , R. Pucci

The low-energy electronic properties of strained graphene are usually obtained by transforming the bond vectors according to the Cauchy-Born rule. In this work, we derive a new effective Dirac Hamiltonian by assuming a more general…

Mesoscale and Nanoscale Physics · Physics 2018-07-09 Maurice Oliva-Leyva , Chumin Wang

In this work we study theoretically the electronic properties of a sheet of graphene grown on a periodic heterostructure substrate. We write an effective Dirac equation, which includes a dependence of both the band gap and the Fermi…

Materials Science · Physics 2014-11-12 Jonas R. F. Lima , F. Moraes

Electrons moving in graphene behave as massless Dirac fermions, and they exhibit fascinating low-frequency electrical transport phenomena. Their dynamic response, however, is little known at frequencies above one terahertz (THz). Such…

We show that the low-energy electronic structure of graphene under a one-dimensional inhomogeneous magnetic field can be mapped into that of graphene under an electric field or vice versa. As a direct application of this transformation, we…

Mesoscale and Nanoscale Physics · Physics 2010-05-31 Liang Zheng Tan , Cheol-Hwan Park , Steven G. Louie

We address spin polarization dependence of graphene's Fermi liquid properties quantitatively using a microscopic Random Phase Approximation theory in an interacting spin-polarized Dirac electron system. We show an enhancement of the…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Alireza Qaiumzadeh , Kh. Jahanbani , Reza Asgari

At low energy, electrons in doped graphene sheets behave like massless Dirac fermions with a Fermi velocity which does not depend on carrier density. Here we show that modulating a two-dimensional electron gas with a long-wavelength…

Mesoscale and Nanoscale Physics · Physics 2009-06-29 M. Gibertini , A. Singha , V. Pellegrini , M. Polini , G. Vignale , A. Pinczuk , L. N. Pfeiffer , K. W. West

We induced periodic biaxial tensile strain in polycrystalline graphene by wrapping it over a substrate with repeating pillar-like structures with a periodicity of 600 nm. Using Raman spectroscopy, we determined to have introduced biaxial…

Materials Science · Physics 2015-11-09 Marjan Aslani , C. Michael Garner , Suhas Kumar , Dennis Nordlund , Piero Pianetta , Yoshio Nishi

We study fluctuations of the conductance of micron-sized graphene devices as a function of the Fermi energy and magnetic field. The fluctuations are studied in combination with analysis of weak localization which is determined by the same…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 D. W. Horsell , A. K. Savchenko , F. V. Tikhonenko , K. Kechedzhi , I. V. Lerner , V. I. Fal'ko

Recently, the strain engineering of two-dimensional materials such as graphene has attracted considerable attention for its great potential in functional nanodevices. Here, we theoretically and experimentally investigate the strain…

Optics · Physics 2015-11-03 Fei Xu , Jin-hui Chen , Yan-qing Lu

We report measurements of the cyclotron mass in graphene for carrier concentrations n varying over three orders of magnitude. In contrast to the single-particle picture, the real spectrum of graphene is profoundly nonlinear so that the…